Harvesting and Growing Yeast from a Commercial Bottle

In relation to growing a starter via this method, how does one know what one is starting with (number of yeast cells)?

I understand the principles involved with growing a healthy number of cells, but if you’re unsure what you’re beginning with, how does this work?

A finished beer will have, at most, roughly a million cells per milliliter. So if it was stored cold there could be as many as ~350 million cells in a 12 fl oz bottle. More than likely, it’s actually less than 100 million. So the key is to start with a very small volume of wort and step up several times. I like to start with 50 mL of wort, then 250 mL, then 1 L, give or take. At that point you should have roughly 50-100 billion cells and you can treat it like a pack or vial.

Great information.  Thank you.  That’s exactly what I needed to know.

Can’t wait to get started on the next adventure in this obsession…